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| author |   Maxim Levitsky <mlevitsk@redhat.com> | 2021-07-15 01:56:24 +0300 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2021-08-16 09:48:27 -0400 |
| commit | 0f923e07124df069ba68d8bb12324398f4b6b709 (patch) | |
| tree | e2fb5efdcf2bb619c2bd3cd6b04463bf6644a1c0 /arch/x86/kvm/svm/nested.c | |
| parent | Merge branch 'kvm-tdpmmu-fixes' into kvm-master (diff) | |
| download | wireguard-linux-0f923e07124df069ba68d8bb12324398f4b6b709.tar.xz wireguard-linux-0f923e07124df069ba68d8bb12324398f4b6b709.zip | |
KVM: nSVM: avoid picking up unsupported bits from L2 in int_ctl (CVE-2021-3653)
* Invert the mask of bits that we pick from L2 in
nested_vmcb02_prepare_control
* Invert and explicitly use VIRQ related bits bitmask in svm_clear_vintr
This fixes a security issue that allowed a malicious L1 to run L2 with
AVIC enabled, which allowed the L2 to exploit the uninitialized and enabled
AVIC to read/write the host physical memory at some offsets.
Fixes: 3d6368ef580a ("KVM: SVM: Add VMRUN handler")
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm/nested.c')
| -rw-r--r-- | arch/x86/kvm/svm/nested.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 61738ff8ef33..28381ca5221c 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -503,7 +503,11 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) { - const u32 mask = V_INTR_MASKING_MASK | V_GIF_ENABLE_MASK | V_GIF_MASK; + const u32 int_ctl_vmcb01_bits = + V_INTR_MASKING_MASK | V_GIF_MASK | V_GIF_ENABLE_MASK; + + const u32 int_ctl_vmcb12_bits = V_TPR_MASK | V_IRQ_INJECTION_BITS_MASK; + struct kvm_vcpu *vcpu = &svm->vcpu; /* @@ -535,8 +539,8 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) vcpu->arch.l1_tsc_offset + svm->nested.ctl.tsc_offset; svm->vmcb->control.int_ctl = - (svm->nested.ctl.int_ctl & ~mask) | - (svm->vmcb01.ptr->control.int_ctl & mask); + (svm->nested.ctl.int_ctl & int_ctl_vmcb12_bits) | + (svm->vmcb01.ptr->control.int_ctl & int_ctl_vmcb01_bits); svm->vmcb->control.virt_ext = svm->nested.ctl.virt_ext; svm->vmcb->control.int_vector = svm->nested.ctl.int_vector; |